JP4020007B2 - Electronic value exchange system and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for distributing electronic value, which is information that represents the value electronically, and in particular, an electronic value exchange method and electronic value exchange for exchanging electronic values such as electronic money and electronic tickets fairly. Relates to a device for:
[0002]
[Prior art]
By using the original data distribution method in Patent Document 1, the electronic value, which is information representing the value electronically, is issued to a user device such as an IC card and used while preventing fraud such as copying or forgery. It can be distributed safely, for example, by transferring between user devices and exercising from user devices. For example, the above method makes it possible to distribute electronic tickets that electronically represent tickets, electronic money that electronically represents money, and the like.
[0003]
However, the method itself does not provide a means for trading electronic value fairly. Here, fair trade means an electronic value that meets the condition that both parties to the transaction will not lose the electronic value of the transaction object without obtaining or obtaining a guarantee to obtain the electronic value for consideration. It refers to mutual exchange.
[0004]
In order to trade the electronic value realized by the above method fairly, it is necessary to use a method such as intermediating the transaction by a third party device and performing a transaction by combining a plurality of electronic value transfers. Become.
[0005]
Hereinafter, as a first method, a conventional method for performing a fair electronic value transaction through the mediation of a third-party device will be described using an example. Here, a case will be described in which the electronic value V1 stored in the user device U1 and the electronic value V2 stored in the user device U2 are exchanged in a fair manner through the mediation of the third party device T.
[0006]
In this case, 1) U1 sends V1 to T. 2) U2 sends V2 to T. 3) T confirms that both V1 and V2 are ready, and sends V2 to U1 and V1 to U2. The above-described steps can realize the above fair exchange transaction.
[0007]
The second method includes a method using sequential disclosure of electronic information. In other words, in the exchange transaction of V1 and V2, the fairness of the transaction can be satisfied by disclosing bit sequences for the transmission of V1 and V2 by U1 and U2 little by little. .
[0008]
[Patent Document 1]
JP 2001-143209 A
[0009]
[Problems to be solved by the invention]
However, in the method of mediating the above third party device, it is necessary to always communicate with the third party device when making a transaction. For this reason, there are problems such as concentrated loads on third party devices and difficulty in use in environments where connectivity to public networks such as the Internet is not ensured.
[0010]
In addition, the method using sequential disclosure has to satisfy additional conditions such as low transaction execution efficiency due to a significant increase in the number of communications associated with transactions, and U1 and U2 computing performance being almost equivalent. There are problems such as being.
[0011]
The present invention has been made in view of the above points, and under normal conditions, that is, the communication path between U1 and U2 is not lost in the period from the start to the end of the transaction, and both U1 and U2 In transactions where the condition of cooperating with the fulfillment of the transaction is fulfilled, it is possible to exchange electronic values with a practical number of communications between U1 and U2 only, and under abnormal conditions, It is an object of the present invention to provide an electronic value exchange method and apparatus capable of restoring the fairness of a transaction using a third party device even in the middle of the transaction.
[0012]
[Means for Solving the Problems]
The above-described problem is that, when the exchange is interrupted in the process of exchanging the electronic value between the first storage means and the second storage means while preventing falsification or duplication of the electronic value, the determination means Determining cancellation or completion; and
When the determination result by the determination unit is cancellation, the cancellation unit sets the storage state of the electronic value in both the first storage unit and the second storage unit to the state before the exchange is performed. When,
When the result of determination by the determination means is complete, the completion means sets the electronic value storage state in both the first storage means and the second storage means to the state after the exchange is performed. Step and
It can be solved by an electronic value exchange method characterized by comprising
[0013]
According to the present invention, the electronic value can be exchanged while preventing falsification and duplication, and even if the exchange is interrupted in the process, the state before the exchange is performed according to the result of the judgment by the judging means. Or the state after the exchange is performed, the fairness of the transaction can be restored.
[0014]
  Also,As described in claim 1,The electronic value exchange method of the present invention is a method for exchanging the first electronic value stored in the first user device and the second electronic value stored in the second user device,
  The first user deviceThe starting means ofGenerating a first random number;Using the first random number, the first session informationGenerating step;Storing information indicating the start as a first session state in the first user device, obtaining a first electronic value from the storage means,Start information that is information including the first session information and the first electronic valueSend to the second user device via the first communication meansPerforming a start step comprising:
  Said second user deviceMeans of consensusThe start information and the first electronic valueReceive via the first communication meansSteps,Obtaining a second electronic value from the storage means;Generating a second random number; and the second random numberBy applying a one-way function toGenerating second session information;Information indicating validity is stored in the second user device as the second session state.Steps,SaidThe first electronic value,SaidThe second electronic value andSaidFirst session informationBy applying a one-way function to information connected toA step of generating agreement target information, a step of generating an electronic signature Sa for the agreement target information and the second session information, and the second electronic valueFrom the storage meansDeleting the agreement object information, the second session information, the agreement information that is information including the electronic signature Sa, and the second electronic value.Send to the first user device via the first communication meansAnd an agreement step including
  The first user deviceThe first confirmation means ofThe agreement information and the second electronic valueReceive via the first communication meansSteps,A one-way function is applied to information obtained by verifying the electronic signature Sa using the public key of the second user device and connecting the first electronic value, the second electronic value, and the first session information. Including verifying whether the information obtained by the action and the agreement target information included in the agreement information are equal.A first verification step for performing the verification;Information indicating validity is stored in the first user device as the first session state.And the second session informationFromGenerating an electronic signature Se, and the first electronic valueFrom storage meansDeleting the first confirmation information, which is information including the second session information and the electronic signature Se.Send to the second user device via the first communication meansPerforming a first confirmation step comprising:
  Said second user deviceThe second confirmation means ofThe first confirmation informationReceive via the first communication meansSteps,Verification of the electronic signature Se using the public key of the first user device, the second session information included in the first confirmation information, and the second session information included in the agreement information. And check for equalityA second verification step for performing the verification;If the verification is successful,The second session stateFrom the second user deviceAnd erasing the first electronic valueIn storage meansStoring the second confirmation information as the second random number;Send to the first user device via the first communication meansA second verification step comprising:
  The first user deviceThe end means ofThe second confirmation informationReceive via the first communication meansSteps,Including verifying whether information obtained by applying a one-way function to the second random number is equal to the second session informationA third verification step for performing the verification;If the verification is successful,The first session stateFrom the first user deviceAnd erasing the second electronic valueIn storage meansA step of storing and executing an ending step comprisingElectronic value exchange method,
  When the verification in the second verification step executed by the second confirmation unit of the second user device fails, the cancellation request unit of the second user device sends information indicating suspension to the second Storing in the second user device as the session state of the user, generating a digital signature Sab for information including information indicating the cancellation request and the agreement information, information indicating the cancellation request, and the agreement information And cancellation request information that is information including the electronic signature Sab. Performing a cancellation request step including the step of transmitting to the third party device via the communication means of 2,
  The cancellation determination unit of the third party device receives the cancellation request information via the second communication unit, and verifies the electronic signature Sab using the public key of the second user device. If information indicating cancellation or information indicating completion is not stored in the third party device as the third session state, the fourth verification step is performed, and information indicating cancellation is set as the third session state as the third session state. An electronic value exchange method comprising: a step of storing in a user device;Can also be configured.
[0016]
  Also,As described in claim 2, the electronic value exchange method of the present invention comprises:  A method of exchanging a first electronic value stored in a first user device and a second electronic value stored in a second user device,
The start means of the first user device generates a first random number, generates first session information using the first random number, and indicates information indicating the start of the first session. A step of storing in the first user device as a state, a step of acquiring a first electronic value from a storage means, start information which is information including the first session information, and the first electronic value Transmitting to the second user device via the first communication means, and executing a start step comprising:
A step in which the agreement means of the second user device receives the start information and the first electronic value via the first communication means; and a step of obtaining a second electronic value from the storage means; Generating a second random number; generating a second session information by applying a one-way function to the second random number; and information indicating validity as the second session state. Storing in the two user devices, and generating the agreement target information by applying a one-way function to the information obtained by concatenating the first electronic value, the second electronic value, and the first session information. A step of generating an electronic signature Sa for the agreement target information and the second session information, a step of deleting the second electronic value from the storage means, Agreement information, which is information including intention information, the second session information, and the electronic signature Sa, and the second electronic value are transmitted to the first user device via the first communication means. And performing an agreement step comprising:
A first confirmation unit of the first user device receiving the agreement information and the second electronic value via the first communication unit; and disclosure of the second user device. Information obtained by verifying the electronic signature Sa using a key and applying a one-way function to information obtained by concatenating the first electronic value, the second electronic value, and the first session information; and A first verification step including verification of whether the agreement target information included in the agreement information is equal, and information indicating validity are stored in the first user device as the first session state. Information including: a step of generating an electronic signature Se from the second session information; a step of deleting the first electronic value from the storage means; and the second session information and the electronic signature Se. Is Sending to the second user device via a first confirmation information said first communication means, executes a first confirmation step including,
The second confirmation unit of the second user device receives the first confirmation information via the first communication unit, and the public key of the first user device is used. Second verification is performed including verification of the electronic signature Se and verification of whether the second session information included in the first confirmation information is equal to the second session information included in the agreement information. A verification step; if the verification is successful, erasing the second session state from the second user device; storing the first electronic value in a storage means; Transmitting a second confirmation information which is a random number to the first user device via the first communication means, and performing a second confirmation step,
The termination means of the first user device is obtained by receiving the second confirmation information via the first communication means and applying a one-way function to the second random number. A third verification step that includes verification whether information is equal to the second session information; and if the verification is successful, erase the first session state from the first user device An electronic value exchange method for executing an ending step including: a step; and storing the second electronic value in a storage means;
  When the verification in the third verification step executed by the termination means of the first user device fails,The first user deviceThe completion request means isA step of generating an electronic signature Sco for information including information indicating a completion request and the agreement information; and completion request information which is information including the information indicating the completion request, the agreement information, and the electronic signature Sco.Is transmitted to the third party device via the second communication means.And a completion request step including
  The third party deviceThe completion determining means is connected via the second communication means.The completion request informationReceiveAnd steps toUsing the public key of the first user device, the electronic signature ScoA fifth verification step for performing the verification;If no information indicating cancellation or information indicating completion is stored in the third party device as the third session state, information indicating completion is stored in the third party device as the third session state.And a completion determination step includingIt can also be configured as an electronic value exchange method characterized by.
[0017]
  Further, as described in claim 3, in the electronic value exchange method according to claim 2,  When the completion determination unit of the third party device determines that information indicating cancellation as the third session state is stored in the third party device,The third party deviceThe cancellation permission means forA step of generating an electronic signature Sabor for information including information indicating cancellation permission and the agreement information; and cancellation permission information which is information including information indicating cancellation permission, the agreement information, and the electronic signature Sabor.Send to the first user device via the second communication meansAnd a revocation permission step including:
  The first user deviceThe means for performing cancellation ofThe revocation permission informationReceive via the second communication meansAnd steps toUsing the public key of the third party device, the electronic signature SaborA sixth verification step for performing verification and the first session state;From the first user devicePerforming a revocation performing step comprising: erasing; and storing the first electronic value in a storage means.May be.
[0018]
  In addition, as described in claim 4, in the electronic value exchange method according to claim 1, the completion determination means of the third party device includes information indicating cancellation as the third session state. If it is determined that it is stored in a three-party device,The third party deviceThe cancellation permission means forA step of generating an electronic signature Sabort for information including information indicating cancellation permission and the agreement information; and cancellation permission information which is information including information indicating cancellation permission, the agreement information, and the electronic signature Sabort.Send to the second user device via the second communication meansAnd a revocation permission step including:
  Of the second user deviceCanceling means are:The revocation permission informationReceive via the second communication meansAnd steps toUsing the public key of the third party device, the electronic signature SaborA seventh verification step for performing verification, and the second session state.From the second user deviceAnd erasing the second electronic valueIn storage meansPerforming a revocation performing step including storingMay be.
[0019]
  Further, as described in claim 5, in the electronic value exchange method according to claim 2,  When the third party device completion determination means determines that information indicating completion as the third session state is held in the third party device,The third party deviceThe completion permission means isA step of generating an electronic signature Commit for information including information indicating completion permission and the agreement information, and completion permission information which is information including information indicating the completion permission, the agreement information, and the electronic signature Commit.Send to the first user device via the second communication meansAnd a completion permission step including:
  The first user deviceCompletion means ofThe completion permission informationReceive via the second communication meansAnd steps toUsing the public key of the third party device, the electronic signature ScommitAn eighth verification step for performing verification and the first session state;From the first user deviceAnd erasing the second electronic valueIn storage meansPerforming a completion fulfillment step comprising:May be.
[0020]
  In addition, as described in claim 6, in the electronic value exchange method according to claim 1, the completion determination unit of the third party device includes information indicating completion as the third session state. If it is determined that it is stored in the three-party device,The third party deviceThe completion permission means is  A step of generating an electronic signature Commit for information including information indicating completion permission and the agreement information, and completion permission information which is information including information indicating completion permission, the agreement information, and the electronic signature Commit.Send to the second user device via the second communication meansAnd a completion permission step including:
  Said second user deviceCompletion means ofThe completion permission informationReceive via the second communication meansAnd steps toUsing the public key of the third party device, the electronic signature ScommitA ninth verification step for performing the verification and the second session state;From the second user deviceAnd erasing the first electronic valueIn storage meansPerforming a completion fulfillment step comprising:May be.
[0021]
According to the present invention, electronic value can be exchanged between two user devices by the processing of each step as described above. In addition, when an abnormality occurs in the exchange processing between the user devices, it can be guaranteed that either the cancellation or the completion of the exchange is performed using the third party device. Furthermore, at this time, the contents of the electronic value to be exchanged can be kept secret from the third party device. The present invention can also be configured as an apparatus and a system.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0023]
First, the outline of the embodiment will be described with reference to FIG. The electronic value exchange system shown in FIG. 1 includes a first storage unit 10 that stores a first electronic value 101, a second storage unit 20 that stores a second electronic value 201, an exchange unit 30, and a determination. Means 40, cancellation means 50, and completion means 60 are provided.
[0024]
The exchanging means 30 is means for exchanging the first electronic value 101 and the second electronic value 201 between the first storing means 10 and the second storing means 20 while preventing falsification or duplication of the electronic value. It is. The determination unit 40 determines cancellation or completion of the exchange when the exchange by the exchange unit 30 is interrupted. Further, the canceling unit 50 exchanges the storage state of the electronic value in both the first storing unit 10 and the second storing unit 20 by the exchanging unit 30 when the determination result by the determining unit 40 is cancelled. It has a function to make it a state before being performed. Further, when the determination result by the determination unit 40 is completed, the completion unit 60 exchanges the electronic value storage state in both the first storage unit 10 and the second storage unit 20 by the exchange unit 30. It has a function to make it a state after being performed.
[0025]
As described above, if an electronic value exchange system is used, it can be exchanged while preventing falsification or duplication of electronic value, and even if the exchange is interrupted in the process, the exchange is performed according to the result of the judgment by the judgment means. It is possible to restore the fairness of the transaction since it can be in the state before the exchange is performed or the state after the exchange is performed.
[0026]
Hereinafter, embodiments of the present invention will be described in more detail.
[0027]
FIG. 2 is a diagram showing the overall configuration of the electronic value exchange system of the present invention. In the figure, the user device 1 and the user device 2 are connected via the communication means 4, and the user device 101 is deleted after deleting the electronic value 101 stored in the user device 1 via the communication means 4. 2 shows a case where an exchange transaction is performed in which the electronic value 201 stored in the user device 2 and further stored in the user device 1 is deleted and stored in the user device 1.
[0028]
Furthermore, the system shown in FIG. 2 includes a third party device 3 connected to the user devices 1 and 2 via the communication means 5. When the user device 1 and the user device 2 recognize an abnormality in the execution of the exchange transaction, such as detection of the interruption of the communication means 4, the user device 1 or 2 that has recognized the abnormality is transferred to the third party device 3. On the other hand, information corresponding to the time of occurrence of the abnormality is transmitted.
[0029]
The third party device 3 determines whether the exchange transaction should be canceled or completed according to the transmitted information, and returns information corresponding to the determination result to the user device of the transmission source. The user device that receives the information returned from the third party device cancels the exchange transaction according to the confirmation result and restores the electronic value, or assumes that the exchange transaction is completed and exchanges The electronic value that was was stored.
[0030]
Here, the communication unit 4 is a temporary communication unit and does not require the user devices 1 and 2 to be always connected. Further, the communication means 5 is also a temporary communication means and does not require constant connection between the user device and the third party device. The communication means 4 and 5 may be provided by the same communication network.
[0031]
Next, the configuration and operation of each device will be described in detail.
[0032]
FIG. 3 is a diagram illustrating a configuration of the user device 1 according to the embodiment of the present invention. The user apparatus 1 shown in FIG. 1 includes a storage unit 10, a start unit 11, a first confirmation unit 12, an end unit 13, a completion request unit 14, a cancellation execution unit 15, and a completion execution unit 16. Here, the user device 1 is typically realized by using a tamper resistant device such as an IC card, and prevents falsification of the program realizing each means and the stored data in the storage means.
[0033]
FIG. 4 is a diagram showing a configuration of the user device 2 according to the embodiment of the present invention. The user apparatus 2 shown in FIG. 1 includes a storage unit 20, an agreement unit 21, a second confirmation unit 22, a cancellation request unit 23, a cancellation execution unit 24, and a completion execution unit 25. Here, similarly to the user device 1, the user device 2 is typically realized by using a tamper-proof device such as an IC card, and prevents falsification of the program for realizing each means and the stored data in the storage means. To do.
[0034]
FIG. 5 is a diagram showing a configuration of the third party device 3 according to the embodiment of the present invention. The third-party device 3 shown in the figure includes a cancellation determination unit 31, a completion determination unit 32, a cancellation permission unit 33, and a completion permission unit 34. Here, the third party device is typically realized as a server connected to a public network such as the Internet, and waits for a connection from the user device.
[0035]
As the communication means 4, two IC card reader / writers interconnected via a communication medium such as an infrared communication path or the Internet can be used. Further, as the communication means 5, an IC card reader / writer connected to a third party device via a communication medium such as the Internet can be used.
[0036]
A method for fairly exchanging the electronic value 101 stored in the storage means 10 and the electronic value 102 stored in the storage means 20 using each device having the above-described configuration will be described below.
[0037]
In the following explanation, the user device 1 discloses the public key certificate CertP1 including the public key P1, the user device 2 discloses the public key certificate CertP2 including the public key P2, and the third party device 3 discloses the public key certificate CertP2. Assume that the public key certificate CertP3 including the key P3 is held in advance. Here, it is assumed that CertP1 and CertP2 are issued by the user certificate authority that is the first certificate authority, and CertP3 is a public key certificate that is issued by the third party certificate authority that is the second certificate authority. .
[0038]
Electronic value exchange by this method is started by executing the following main processing. If an abnormality occurs in the execution of the main process, the execution of the main process is interrupted, and the execution branches to a cancellation request process or a completion request process. After execution of the cancellation request process and the completion request process, execution branches to a cancellation execution process or a completion execution process depending on the state of the third party device. These branch conditions will be described in the following description of the processing.
[0039]
(Main processing)
The procedure of the main process will be described with reference to FIGS.
[0040]
First, the starting unit 11 of the user device 1 executes the following processing.
[0041]
Step 101) Generate a first random number n1.
[0042]
Step 102) First session information s1 = n1 corresponding to n1 is generated.
[0043]
Step 103) Define the first session state as "started". For example, information indicating “start” is stored in association with “first session state”.
[0044]
Step 104) The electronic value 101 is referred from the storage means 10. Let this be V1.
[0045]
Step 105) O = s1 and V1, that is, (O, V1) is output to the communication means 4.
[0046]
The communication means 4 transfers (O, V1) from the user device 1 to the user device 2.
[0047]
Subsequently, the agreement means 21 of the user device 2 executes the following processing.
[0048]
Step 106) Obtain O and V1 from the communication means 4.
[0049]
Step 107) The electronic value 201 is referred to from the storage means 20. This is V2.
[0050]
Step 108) Generate a second random number n2.
[0051]
Step 109) The second session information s2 = H (n2) corresponding to n2 is generated by using the one-way function H ().
[0052]
Step 110) Define the second session state as "valid". For example, information indicating “valid” is stored in association with “second session state”.
[0053]
Step 111) The agreement target information Ao = H (V1 || V2 || s1) is generated using the one-way function H (). Where || represents concatenation.
[0054]
Step 112) Sa = SigP2 (Ao || s2) is generated. Here, SigP2 () is a signature function that generates an electronic signature that can be verified with the public key P2. ESIGN or ECDSA can be used as such a signature function.
[0055]
Step 113) Delete V2 from the storage means 20.
[0056]
Step 114) A = (Ao, s2, Sa), V2 and CertP2 are output to the communication means 4.
[0057]
Then, the communication means 4 transfers (A, V2, CertP2) from the user device 2 to the user device 1.
[0058]
Then, the 1st confirmation means 12 of the user apparatus 1 performs the following.
[0059]
Step 115) A and CertP2 are acquired from the communication means 4.
[0060]
Step 116) The following items are verified, and if any of them fails, the subsequent processing is interrupted.
-The first session state is "Started".
-CertP2 is a valid public key certificate by the user certificate authority.
-Successful signature verification of Sa = SigP2 (Ao || s2) using P2.
-Ao = H (V1 || V2 || s1).
[0061]
Step 117) Define the first session state as "valid".
[0062]
Step 118) Generate Se = SigP1 (s2). Here, SigP1 () is a signature function that generates an electronic signature that can be verified with the public key P1.
[0063]
Step 119) Delete V1 from the storage means 10.
[0064]
Step 120) Output E1 = (s2, Se) and CertP1 to the communication means 4.
[0065]
Then, the communication means 4 transfers (E1, CertP1) from the user device 1 to the user device 2. If an abnormality is detected such that this transfer is not performed within a certain period of time, such as a timeout, the user apparatus 2 interrupts the following process and executes a “cancel request process”.
[0066]
Then, the 2nd confirmation means 22 of the user apparatus 2 performs the following.
[0067]
Step 121) E1 and CertP1 are acquired from the communication means 4.
[0068]
Step 122) The following is verified, and if any one of them fails, the subsequent processing is interrupted and "cancellation request processing" is executed.
-The second session state is “valid”.
-CertP1 is a valid public key certificate by the user certificate authority.
-Successful signature verification of Se = SigP1 (s2) using P1.
-S2 included in E1 and s2 included in A must be the same.
[0069]
Step 123) Erase the second session state.
[0070]
Step 124) Store V1 in the storage means 20.
[0071]
Step 125) Output E2 = n2 to the communication means 4.
[0072]
Then, the communication means 4 transfers E2 from the user device 2 to the user device 1. If an abnormality is detected, such as a time-out without this transfer being performed within a certain period of time, the user apparatus 1 interrupts the following process and executes a “completion request process”.
[0073]
Subsequently, the ending unit of the user device 1 executes the following.
[0074]
Step 126) Obtain E2 from the communication means 4.
[0075]
Step 127) The following are verified, and if any of them fails, the subsequent processing is interrupted and "completion request processing" is executed.
-The first session state is "valid".
-s2 = H (n2).
[0076]
Step 128) Clear the first session state.
[0077]
Step 129) V2 is stored in the storage means 10.
[0078]
(End of main processing)
If the main process consisting of the above steps 101 to 128 has been executed to the end, the process is terminated. At this time, the electronic value 201 is stored in the storage means 10 of the user apparatus 1 and the electronic value 101 is stored in the storage means 20 of the user apparatus 2, and the above-described electronic value is exchanged fairly.
[0079]
(Cancellation request processing)
Next, the procedure of the “cancel request process” executed by the user apparatus 2 in a predetermined case in the main process will be described with reference to FIG.
[0080]
First, the cancellation request unit 23 of the user device 2 executes the following.
[0081]
Step 201) Define the second session state as "pending".
[0082]
Step 202) Generate Sab = SigP2 (Mab || A). Here, Mab is information indicating a cancellation request.
[0083]
Step 203) Rab = (Mab, A, Sab) and CertP2 are output to the communication means 5.
[0084]
The communication means 5 transfers Rab and CertP2 from the user device 2 to the third party device 3. And the cancellation determination means 31 of the third party apparatus 3 performs the following.
[0085]
Step 204) Rab and CertP2 are acquired from the communication means 5.
[0086]
Step 205) The following are verified, and if any of them fails, the subsequent processing is interrupted.
-CertP2 is a valid public key certificate by the user certificate authority.
-The signature verification of Sab = SigP2 (Mab || A) is successful using P2.
[0087]
Step 206) Referring to the third session state, if it is undefined, define it as "Cancel".
[0088]
Step 207) The third session state is referred to, and the process branches depending on the content.
-If it is defined as "Cancel", execute the cancel permission process.
-If it is defined as “Complete”, execute the completion permission process.
[0089]
(End cancellation request processing)
When the processing according to the above procedure ends, the cancellation request processing ends.
[0090]
(Completion request processing)
Next, the procedure of the “completion request process” executed by the user device 1 in a predetermined case in the main process will be described with reference to FIG. The completion request process is executed according to the following procedure.
[0091]
The completion request unit 14 of the user device 1 executes the following.
[0092]
Step 301) Generate Sco = SigP1 (Mco || A). Here, Mco is information indicating a completion request.
[0093]
Step 302) Output Rco = (Mco, A, Sco) and CertP1 to the communication means 5.
[0094]
The communication means 5 transfers Rco and CertP2 from the user device 2 to the third party device 3. And the completion determination means 32 of the third party apparatus 3 performs the following.
[0095]
Step 303) Rco and CertP1 are acquired from the communication means 5.
[0096]
Step 304) The following are verified, and if any of them fails, the subsequent processing is interrupted.
-CertP1 is a valid public key certificate by the user certificate authority.
-Successful signature verification of Sco = SigP1 (Mco || A) using P1.
[0097]
Step 305) Referring to the third session state, if it is not defined, define it as “complete”.
[0098]
Step 306) The third session state is referred to, and the process branches depending on the content.
-If it is defined as "Cancel", execute the cancel permission process.
-If it is defined as “Complete”, execute the completion permission process.
[0099]
(End of completion request processing)
When the process according to the above procedure ends, the completion request process ends.
[0100]
(Cancellation processing)
Next, the procedure of the cancellation permission process executed in a predetermined case in the completion request process or the cancellation request process will be described with reference to FIG.
[0101]
The cancellation permission means 33 of the third party device 3 executes the following processing.
[0102]
Step 401) Generate Sabort = SigP3 (abort || A). Where abort is information indicating permission to cancel.
[0103]
Step 402) Output AT = (abort, A, Sabort) and CertP3 to the communication means 5.
[0104]
Step 403) The communication means 5 transfers AT and CertP3 from the third party device 3 to the user device 1 or the user device 2. Which is transferred depends on the following conditions.
-User device 1 if the pre-process was a completion request process.
-User device 2 if the pre-processing was cancellation request processing.
[0105]
When the user apparatus 1 has received AT and CertP3, the cancel execution means 15 of the user apparatus 1 executes the following.
[0106]
Step 411) Obtain AT and CertP3 from the communication means 5.
[0107]
Step 412) The following is verified, and if any of them fails, the subsequent processing is interrupted.
-The first session state is "valid".
-CertP3 is a valid public key certificate from a third-party device certificate authority.
-Successful signature verification of Sabort = SigP3 (abort || A) using P3.
[0108]
Step 413) The first session state is erased or defined as invalid.
[0109]
Step 414) An electronic value corresponding to V1 is generated and stored in the storage means 10.
[0110]
When the user apparatus 2 has received AT and CertP3, the cancel execution means 24 of the user apparatus 2 executes the following processing.
[0111]
Step 421) Obtain AT and CertP3 from the communication means 5.
[0112]
Step 422) The following is verified, and if any of them fails, the subsequent processing is interrupted.
-The second session state is "pending" or "valid".
-CertP3 is a valid public key certificate from a third-party device certificate authority.
-Successful signature verification of Sabort = SigP3 (abort || A) using P3.
[0113]
Step 423) The second session state is erased or defined as invalid.
[0114]
Step 424) An electronic value corresponding to V2 is generated and stored in the storage means 20.
[0115]
(End of cancellation permission processing)
When the above process ends, the cancellation permission process ends.
[0116]
(Completion permission processing)
Next, the completion permission process executed in a predetermined case in the completion request process or the cancellation request process will be described with reference to FIG.
[0117]
The completion permission means 34 of the third party device 3 executes the following.
[0118]
Step 501) Generate Scommit = SigP3 (commit || A). Here, commit is information indicating completion permission.
[0119]
Step 502) CT = (commit, A, Scommit) and CertP3 are output to the communication means 5.
[0120]
Step 503) The communication means 5 transfers CT and CertP3 from the third party device 3 to the user device 1 or the user device 2. Which is transferred depends on the following conditions.
-User device 1 if the pre-process was a completion request process.
-User device 2 if the pre-processing was cancellation request processing.
[0121]
When the user apparatus 1 has received the CT and CertP3, the completion execution means 16 of the user apparatus 1 executes the following.
[0122]
Step 511) Obtain CT and CertP3 from the communication means 5.
[0123]
Step 512) The following is verified, and if any of them fails, the subsequent processing is interrupted.
-The first session state is "valid".
-CertP3 is a valid public key certificate from a third-party device certificate authority.
-Successful signature verification of Scommit = SigP3 (commit || A) using P3.
[0124]
Step 513) The first session state is erased or defined as invalid.
[0125]
Step 514) An electronic value corresponding to V2 is generated and stored in the storage means 10.
[0126]
When the user apparatus 2 has received the CT and CertP3, the completion execution means 25 of the user apparatus 2 executes the following.
[0127]
Step 521) Obtain CT and CertP3 from the communication means 5.
[0128]
Step 522) The following is verified, and if any one fails, the subsequent processing is interrupted.
-The second session state is "pending" or "valid".
-CertP3 is a valid public key certificate from a third-party device certificate authority.
-Successful signature verification of Scommit = SigP3 (commit || A) using P3.
[0129]
Step 523) Erase the second session state or define it as invalid. .
[0130]
Step 524) An electronic value corresponding to V1 is generated and stored in the storage means 20.
[0131]
(End of completion permission processing)
When the above process ends, the completion permission process ends.
[0132]
In the above embodiment, the electronic values 101 and 201 can be electronic money representing a certain amount of money. Thereby, an electronic money exchange system can be realized. Also, the electronic value 101 is one or more electronic tickets and the electronic value 201 is electronic money representing a certain amount of money, or the electronic value 201 is one or more electronic tickets, By using the electronic value 101 as electronic money representing a certain amount of money, an electronic ticket selling system can be realized.
[0133]
A program for performing processing according to the present embodiment in each device of the system according to the present embodiment is a computer-readable recording medium such as an FD (floppy (registered trademark) disk), MO, ROM, memory card, or CD. -It can be recorded on ROM, DVD, removable disk, etc., stored or distributed. The program can also be provided through a network such as the Internet or e-mail.
[0134]
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.
[0135]
【The invention's effect】
As described above, according to the present invention, electronic value can be exchanged between two user devices. In addition, when an abnormality occurs in the exchange processing between the user devices, it can be guaranteed that either the cancellation or the completion of the exchange is performed using the third party device. Furthermore, at this time, the contents of the electronic value to be exchanged can be kept secret from the third party device.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an electronic value exchange system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of an electronic value exchange system according to an embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a user device 1 in the embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of a user device 2 in the embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of a third party device 3 in the embodiment of the present invention.
FIG. 6 is a diagram showing a procedure of main processing in the embodiment of the present invention.
FIG. 7 is a diagram showing a procedure of main processing in the embodiment of the present invention.
FIG. 8 is a diagram showing a procedure of cancellation request processing according to the embodiment of the present invention.
FIG. 9 is a diagram showing a procedure of a completion request process in the embodiment of the present invention.
FIG. 10 is a diagram showing a procedure of cancellation permission processing in the embodiment of the present invention.
FIG. 11 is a diagram showing a procedure of a completion permission process in the embodiment of the present invention.
[Explanation of symbols]
1, 2 User device
3 Third party equipment
4, 5 Communication means
101 First electronic value
10 First storage means
201 Second electronic value
20 Second storage means
30 exchange means
40 judgment means
50 Cancellation means
60 means of completion
11 Starting means
12 First confirmation means
13 Termination means
14 Completion request means
15 Cancellation means
16 Completion means
21 Agreement means
22 Second confirmation means
23 Cancellation request means
24 Cancellation means
25 Completion means
31 Cancellation determination means
32 Completion judging means
33 Cancellation permission means
34 Completion permission means

Claims (12)

A method of exchanging a first electronic value stored in a first user device and a second electronic value stored in a second user device,
The start means of the first user device generates a first random number, generates first session information using the first random number , and indicates information indicating the start of the first session. A step of storing in the first user device as a state, a step of acquiring a first electronic value from a storage means , start information which is information including the first session information, and the first electronic value Transmitting to the second user device via the first communication means, and executing a start step comprising:
A step in which the agreement means of the second user device receives the start information and the first electronic value via the first communication means; and a step of obtaining a second electronic value from the storage means; the generating a second random number, and generating a second session information by the action of one-way function to said second random number, the information indicating valid as the second session state first and storing the second user device, generating agreement object information by applying a one-way function to the first electronic value, the second electronic value, and information connecting the first session information the method comprising the steps of: generating an electronic signature Sa and the agreement object information for the second session information, a step of deleting the second electronic value from the storage means, wherein And agreement information is information including the meaning object information and the second session information and the electronic signature Sa, the first user device via the first communication means and said second electronic value of perform the agreement step including a step of transmitting, a,
A first confirmation unit of the first user device receiving the agreement information and the second electronic value via the first communication unit; and disclosure of the second user device. Information obtained by verifying the electronic signature Sa using a key and applying a one-way function to information obtained by concatenating the first electronic value, the second electronic value, and the first session information; and A first verification step including verification of whether the agreement target information included in the agreement information is equal , and information indicating validity are stored in the first user device as the first session state. Information including: a step of generating an electronic signature Se from the second session information; a step of deleting the first electronic value from the storage means; and the second session information and the electronic signature Se. Is Sending to the second user device via a first confirmation information said first communication means, executes a first confirmation step including,
The second confirmation unit of the second user device receives the first confirmation information via the first communication unit, and the public key of the first user device is used. Second verification is performed including verification of the electronic signature Se and verification of whether the second session information included in the first confirmation information is equal to the second session information included in the agreement information . A verification step; if the verification is successful, erasing the second session state from the second user device ; storing the first electronic value in a storage means ; Transmitting a second confirmation information which is a random number to the first user device via the first communication means, and performing a second confirmation step,
The termination means of the first user device is obtained by receiving the second confirmation information via the first communication means and applying a one-way function to the second random number. A third verification step that includes verification whether information is equal to the second session information; and if the verification is successful, erase the first session state from the first user device An electronic value exchanging method for executing an ending step including a step and a step of storing the second electronic value in a storage means ;
When the verification in the second verification step executed by the second confirmation unit of the second user device fails, the cancellation request unit of the second user device sends information indicating suspension to the second Storing in the second user device as the session state of the user, generating a digital signature Sab for information including information indicating the cancellation request and the agreement information, information indicating the cancellation request, and the agreement information And a step of transmitting cancellation request information, which is information including the electronic signature Sab, to the third party device via the second communication means,
The cancellation determination unit of the third party device receives the cancellation request information via the second communication unit, and verifies the electronic signature Sab using the public key of the second user device. If information indicating cancellation or information indicating completion is not stored in the third party device as the third session state, the fourth verification step is performed, and information indicating cancellation is set as the third session state as the third session state. And a revocation determination step including the step of storing in the person device . A method of exchanging a first electronic value stored in a first user device and a second electronic value stored in a second user device,
The start means of the first user device generates a first random number, generates first session information using the first random number, and indicates information indicating the start of the first session. A step of storing in the first user device as a state, a step of acquiring a first electronic value from a storage means, start information which is information including the first session information, and the first electronic value Transmitting to the second user device via the first communication means, and executing a start step comprising:
A step in which the agreement means of the second user device receives the start information and the first electronic value via the first communication means; and a step of obtaining a second electronic value from the storage means; Generating a second random number; generating a second session information by applying a one-way function to the second random number; and information indicating validity as the second session state. Storing in the two user devices, and generating the agreement target information by applying a one-way function to the information obtained by concatenating the first electronic value, the second electronic value, and the first session information. A step of generating an electronic signature Sa for the agreement target information and the second session information, a step of deleting the second electronic value from the storage means, Agreement information, which is information including intention information, the second session information, and the electronic signature Sa, and the second electronic value are transmitted to the first user device via the first communication means. And performing an agreement step comprising:
A first confirmation unit of the first user device receiving the agreement information and the second electronic value via the first communication unit; and disclosure of the second user device. Information obtained by verifying the electronic signature Sa using a key and applying a one-way function to information obtained by concatenating the first electronic value, the second electronic value, and the first session information; and A first verification step including verification of whether the agreement target information included in the agreement information is equal, and information indicating validity are stored in the first user device as the first session state. Information including: a step of generating an electronic signature Se from the second session information; a step of deleting the first electronic value from the storage means; and the second session information and the electronic signature Se. Is Sending to the second user device via a first confirmation information said first communication means, executes a first confirmation step including,
The second confirmation unit of the second user device receives the first confirmation information via the first communication unit, and the public key of the first user device is used. Second verification is performed including verification of the electronic signature Se and verification of whether the second session information included in the first confirmation information is equal to the second session information included in the agreement information. A verification step; if the verification is successful, erasing the second session state from the second user device; storing the first electronic value in a storage means; Transmitting a second confirmation information which is a random number to the first user device via the first communication means, and performing a second confirmation step,
The termination means of the first user device is obtained by receiving the second confirmation information via the first communication means and applying a one-way function to the second random number. A third verification step that includes verification whether information is equal to the second session information; and if the verification is successful, erase the first session state from the first user device An electronic value exchanging method for executing an ending step including a step and a step of storing the second electronic value in a storage means;
When the verification in the third verification step executed by the end unit of the first user device fails , the completion request unit of the first user device includes information indicating a completion request and the agreement information A step of generating an electronic signature Sco for the information including: the completion request information which is information including the information indicating the completion request, the agreement information, and the electronic signature Sco via a second communication means. Executing a completion request step comprising: sending to the device ;
The completion determination unit of the third party device receives the completion request information via the second communication unit, and verifies the electronic signature Sco using the public key of the first user device. If information indicating cancellation or information indicating completion as the third session state is not stored in the third party device, information indicating completion is set as the third session state as the third session state. And a completion determination step including the step of storing in the person device . When the completion determination unit of the third party device determines that information indicating cancellation as the third session state is stored in the third party device , the cancellation permission unit of the third party device A step of generating an electronic signature Sabot for information including information indicating permission and the agreement information; and revocation permission information which is information including the information indicating permission of revocation, the agreement information, and the electronic signature Sabor . Performing a cancellation permission step including the step of transmitting to the first user device via two communication means ,
The revocation performing means of the first user device receives the revocation permission information via the second communication means, and verifies the electronic signature Sabor using the public key of the third party device. Performing a revocation performing step comprising: performing a sixth verification step; erasing the first session state from the first user device; and storing the first electronic value in a storage means. The electronic value exchange method according to claim 2 , wherein: When the completion determination unit of the third party device determines that information indicating cancellation as the third session state is stored in the third party device , the cancellation permission unit of the third party device wherein the information indicating the authorization and generating an electronic signature Sabort for information including the agreement information, the revocation permission information is information including information indicating the cancellation permission and the agreement information and the electronic signature Sabort first Transmitting to the second user device via two communication means, and executing a cancellation permission step including:
The revocation performing means of the second user device receives the revocation permission information via the second communication means, and verifies the electronic signature Sabor using the public key of the third party device. Performing a revocation performing step comprising: performing a seventh verification step; erasing the second session state from the second user device; and storing the second electronic value in a storage means. The electronic value exchange method according to claim 1 , wherein: When the third party device completion determination means determines that information indicating completion as the third session state is held in the third party device , the third party device completion permission means, the information indicating the commitment permission, and generating an electronic signature Scommit for information including the agreement information, the commitment permission information being the information containing the commitment permission information indicating the said agreement information and the electronic signature Scommit Transmitting to the first user device via a second communication means, and executing a completion permission step comprising:
The completion executing means of the first user device receives the completion permission information via the second communication means, and verifies the electronic signature Commit using the public key of the third party device. Performing a completion performing step comprising: performing an eighth verification step; erasing the first session state from the first user device; and storing the second electronic value in a storage means. The electronic value exchange method according to claim 2 , wherein: When the completion determination unit of the third party device determines that information indicating completion as the third session state is stored in the third party device , the completion permission unit of the third party device , the information indicating the commitment permission, and generating an electronic signature Scommit for information including the agreement information, the commitment permission information being the information containing the commitment permission information indicating the said agreement information and the electronic signature Scommit Transmitting to the second user device via a second communication means, and executing a completion permission step comprising:
The completion execution means of the second user device receives the completion permission information via the second communication means, and verifies the electronic signature Commit using the public key of the third party device. Performing a completion performing step comprising: performing a ninth verification step; erasing the second session state from the second user device; and storing the first electronic value in a storage means. The electronic value exchange method according to claim 1 , wherein: First user device, second user device, first communication means for performing communication between first user device and second user device, third party device, and third party A first electronic value stored in the first user device, comprising a second communication means for communicating between the device and the first user device and the second user device; An electronic value exchange system for exchanging the second electronic value stored in the two user devices,
  The start means of the first user device generates a first random number, generates first session information using the first random number, and indicates information indicating the start of the first session. A step of storing in the first user device as a state, a step of acquiring a first electronic value from a storage means, start information which is information including the first session information, and the first electronic value Transmitting to the second user device via the first communication means, and executing a start step comprising:
  A step in which the agreement means of the second user device receives the start information and the first electronic value via the first communication means; and a step of obtaining a second electronic value from the storage means; Generating a second random number; generating a second session information by applying a one-way function to the second random number; and information indicating validity as the second session state. Storing in the two user devices, and generating the agreement target information by applying a one-way function to the information obtained by concatenating the first electronic value, the second electronic value, and the first session information. A step of generating an electronic signature Sa for the agreement target information and the second session information, a step of deleting the second electronic value from the storage means, Agreement information, which is information including intention information, the second session information, and the electronic signature Sa, and the second electronic value are transmitted to the first user device via the first communication means. And performing an agreement step comprising:
  A first confirmation unit of the first user device receiving the agreement information and the second electronic value via the first communication unit; and disclosure of the second user device. Information obtained by verifying the electronic signature Sa using a key and applying a one-way function to information obtained by concatenating the first electronic value, the second electronic value, and the first session information; and A first verification step including verification of whether the agreement target information included in the agreement information is equal, and information indicating validity are stored in the first user device as the first session state. Information including: a step of generating an electronic signature Se from the second session information; a step of deleting the first electronic value from the storage means; and the second session information and the electronic signature Se. Is Sending to the second user device via a first confirmation information said first communication means, executes a first confirmation step including,
  The second confirmation unit of the second user device receives the first confirmation information via the first communication unit, and the public key of the first user device is used. Second verification is performed including verification of the electronic signature Se and verification of whether the second session information included in the first confirmation information is equal to the second session information included in the agreement information. A verification step; if the verification is successful, erasing the second session state from the second user device; storing the first electronic value in a storage means; Transmitting a second confirmation information that is a random number of 2 to the first user device via the first communication means, and performing a second confirmation step,
  The termination means of the first user device is obtained by receiving the second confirmation information via the first communication means and applying a one-way function to the second random number. A third verification step that includes verification whether information is equal to the second session information; and if the verification is successful, erase the first session state from the first user device An electronic value exchange system for executing an end step including: a step; and storing the second electronic value in a storage means;
  When the verification in the second verification step executed by the second confirmation unit of the second user device fails, the cancellation request unit of the second user device sends information indicating suspension to the second Storing in the second user device as the session state of the user, generating a digital signature Sab for information including information indicating the cancellation request and the agreement information, information indicating the cancellation request, and the agreement information And a step of transmitting cancellation request information, which is information including the electronic signature Sab, to the third party device via the second communication means,
  The cancellation determination unit of the third party device receives the cancellation request information via the second communication unit, and verifies the electronic signature Sab using the public key of the second user device. If information indicating cancellation or information indicating completion is not stored in the third party device as the third session state, the fourth verification step is performed, and information indicating cancellation is set as the third session state as the third session state. An electronic value exchange system characterized by executing a cancellation determination step including storing in a person device. First user device, second user device, first communication means for performing communication between first user device and second user device, third party device, and third party A first electronic value stored in the first user device, comprising a second communication means for communicating between the device and the first user device and the second user device; An electronic value exchange system for exchanging the second electronic value stored in the two user devices,
The start means of the first user device generates a first random number, generates first session information using the first random number, and indicates information indicating the start of the first session. A step of storing in the first user device as a state, a step of acquiring a first electronic value from a storage means, start information which is information including the first session information, and the first electronic value Transmitting to the second user device via the first communication means, and executing a start step comprising:
A step in which the agreement means of the second user device receives the start information and the first electronic value via the first communication means; and a step of obtaining a second electronic value from the storage means; Generating a second random number; generating a second session information by applying a one-way function to the second random number; and information indicating validity as the second session state. Storing in the two user devices, and generating the agreement target information by applying a one-way function to the information obtained by concatenating the first electronic value, the second electronic value, and the first session information. A step of generating an electronic signature Sa for the agreement target information and the second session information, a step of deleting the second electronic value from the storage means, Agreement information, which is information including intention information, the second session information, and the electronic signature Sa, and the second electronic value are transmitted to the first user device via the first communication means. And performing an agreement step comprising:
A first confirmation unit of the first user device receiving the agreement information and the second electronic value via the first communication unit; and disclosure of the second user device. Information obtained by verifying the electronic signature Sa using a key and applying a one-way function to information obtained by concatenating the first electronic value, the second electronic value, and the first session information; and A first verification step including verification of whether the agreement target information included in the agreement information is equal, and information indicating validity are stored in the first user device as the first session state. comprising the steps you, and generating an electronic signature Se from the second session information, a step of deleting the first electronic value from the storage means, the second session information and said electronic signature Se Information Sending to the second user device via a first confirmation information said first communication means, executes a first confirmation step including,
The second confirmation unit of the second user device receives the first confirmation information via the first communication unit, and the public key of the first user device is used. Second verification is performed including verification of the electronic signature Se and verification of whether the second session information included in the first confirmation information is equal to the second session information included in the agreement information. A verification step; if the verification is successful, erasing the second session state from the second user device; storing the first electronic value in a storage means; Transmitting a second confirmation information which is a random number to the first user device via the first communication means, and performing a second confirmation step,
The termination means of the first user device is obtained by receiving the second confirmation information via the first communication means and applying a one-way function to the second random number. A third verification step that includes verification whether information is equal to the second session information; and if the verification is successful, erase the first session state from the first user device An electronic value exchange system for executing an end step including: a step; and storing the second electronic value in a storage means;
When the verification in the third verification step executed by the end unit of the first user device fails, the completion request unit of the first user device includes information indicating a completion request and the agreement information A step of generating an electronic signature Sco for the information including: the completion request information which is information including the information indicating the completion request, the agreement information, and the electronic signature Sco via a second communication means. Executing a completion request step comprising: sending to the device;
The completion determination unit of the third party device receives the completion request information via the second communication unit, and verifies the electronic signature Sco using the public key of the first user device. If information indicating cancellation or information indicating completion as the third session state is not stored in the third party device, information indicating completion is set as the third session state as the third session state. An electronic value exchange system comprising: a completion determination step including: When the completion determination unit of the third party device determines that information indicating cancellation as the third session state is stored in the third party device, the cancellation permission unit of the third party device A step of generating an electronic signature Sabot for information including information indicating permission and the agreement information; and revocation permission information which is information including the information indicating permission of revocation, the agreement information, and the electronic signature Sabor. Performing a cancellation permission step including the step of transmitting to the first user device via two communication means,
The revocation performing means of the first user device receives the revocation permission information via the second communication means, and verifies the electronic signature Sabor using the public key of the third party device. Performing a revocation performing step comprising: performing a sixth verification step; erasing the first session state from the first user device; and storing the first electronic value in a storage means. The electronic value exchange system according to claim 8, wherein: When the completion determination unit of the third party device determines that information indicating cancellation as the third session state is stored in the third party device, the cancellation permission unit of the third party device Electronic signature Sabort for information including information indicating permission and the agreement information And revocation permission information that is information including the revocation permission information, the agreement information, and the electronic signature Sabort is transmitted to the second user device via the second communication means. And execute a revocation permission step including:
The revocation performing means of the second user device receives the revocation permission information via the second communication means, and verifies the electronic signature Sabor using the public key of the third party device. Performing a revocation performing step comprising: performing a seventh verification step; erasing the second session state from the second user device; and storing the second electronic value in a storage means. The electronic value exchange system according to claim 7 . When the third party device completion determination means determines that information indicating completion as the third session state is held in the third party device, the third party device completion permission means, A step of generating an electronic signature Committee for information including information indicating completion permission and the agreement information; and completion permission information which is information including the information indicating completion permission, the agreement information, and the electronic signature Committee. Transmitting to the first user device via a second communication means, and executing a completion permission step comprising:
The completion executing means of the first user device receives the completion permission information via the second communication means, and verifies the electronic signature Commit using the public key of the third party device. Performing a completion performing step comprising: performing an eighth verification step; erasing the first session state from the first user device; and storing the second electronic value in a storage means. The electronic value exchange system according to claim 8, wherein: When the completion determination unit of the third party device determines that information indicating completion as the third session state is stored in the third party device, the completion permission unit of the third party device, Electronic signature Scommit for information including information indicating completion permission and the agreement information And the completion permission information, which is information including the information indicating the completion permission, the agreement information, and the electronic signature Commit, is transmitted to the second user device via the second communication unit. And a completion permission step including:
  The completion execution means of the second user device receives the completion permission information via the second communication means, and verifies the electronic signature Commit using the public key of the third party device. Performing a completion performing step comprising: performing a ninth verification step; erasing the second session state from the second user device; and storing the first electronic value in a storage means. The electronic value exchange system according to claim 7.

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